1. Field of the Invention
This invention relates to the movement of a lens or other device in and out of an optical path and more particularly, to apparatus for rapidly moving a lens or other object from one fixed position to another and for accurately positioning said object at each fixed position.
This application is related to U.S. patent application Ser. Nos. 582,582, 582,583, 582,584, 582,585, 582,586 and 582,587 all filed on Feb. 22, 1984.
2. Description of the Prior Art
Devices for moving a lens or other object between two fixed location are well-known. However, most such devices operate at a fixed rate of motion throughout the distance of travel and to avoid shock at each end, the rate of motion is slow. Further, the ability to accurately align the position of the object is poor and often the alignment changes with time because of wear caused by the sudden stop at each end of travel.
In the instant invention the drive mechanism provids for rapidly moving a slideable member between two fixed locations by a slider crank mechanism. By so doing the rate of motion of the slideable member is close to zero when it reaches the end of its travel near each end, even through the crank moves with nearly constant angular velocity. This substantially reduces the effect of shock as is often found in prior art devices. A spring loaded drive link is used to allow the slideable member to be preloaded against a stop at each end of its travel. The gentle approach to the stops and the preloading assure accurate, repeatable positioning at each of the two end locations.